TwinCam: Omni-directional Stereoscopic Live Viewing Camera
for Reducing Motion Blur during Head Rotation
Kento Tashiro

Tokyo Metropolitan University
Hino, Tokyo, Japan 191-0065
tashiro@vr.sd.tmu.ac.jp

Tomohiro Amemiya

NTT Communication Science
Laboratories
Atsugi, Kanagawa, Japan 243-0198
amemiya.tomohiro@lab.ntt.co.jp

Toi Fujie

Tokyo Metropolitan University
Hino, Tokyo, Japan 191-0065
fujie@vr.sd.tmu.ac.jp

Koichi Hirota

University of Electro-communications
Chofu, Tokyo 182-8585
hirota@vogue.is.uec.ac.jp

Yasushi Ikei

Tokyo Metropolitan University
Hino, Tokyo, Japan 191-0065
ikei@vr.sd.tmu.ac.jp

Michiteru Kitazaki

Toyohashi University of Technology
Toyohashi, Aichi, Japan 441-8580
mich@tut.jp

Figure 1: TwinCam: 360-degree stereoscopic real-time rendering.

ABSTRACTWe developed an omni-directional stereoscopic live viewing camera(TwinCam) system to reduce the motion blur and latency during
head rotation of a remote user wearing a head mounted display(HMD). The TwinCam system consists of two omni-directional
live cameras (THETA S, Ricoh), rotation mechanisms with a motor,
an image control PC, and an HMD. The camera base rotates synchronously with the azimuth angle of the HMD that the observeris wearing, while each camera lens is at a constant azimuth angle.
This camera configuration greatly reduces image flow on the CMOS
image sensor in the camera, and eventually, the motion blur on theHMD screens when the HMD rotates. The apparent image latency
during the head rotation is minimized by the buffered image. A
user study demonstrated that both reduced motion blur and compensated latency were effective in reducing the virtual reality (VR)sickness symptoms.

ACM Reference format:Kento Tashiro, Toi Fujie, Yasushi Ikei, Tomohiro Amemiya, Koichi Hirota,and Michiteru Kitazaki. 2017. TwinCam: Omni-directional Stereoscopic
Live Viewing Camera for Reducing Motion Blur during Head Rotation. In
Proceedings of SIGGRAPH ’17 Emerging Technologies, Los Angeles, CA, USA,
July 30 - August 03, 2017, 2 pages.
https://doi.org/10.1145/3084822.3084831

1

TWINCAM SYSTEMThe TwinCam system captures two 360-degree real-time videos
that are projected onto two spherical virtual screens from which
left- and right-eye images are clipped to render them on the HMD
as shown in Fig. 1. To maintain the correct binocular parallax, thecamera base (Fig. 2) rotates to the same azimuth angle as the HMD

CCS CONCEPTS• Human-centered computing → Displays and imagers; Virtual reality; • Computing methodologies → 3D imaging;

KEYWORDS
Stereoscopic live image, motion blur, latency, telepresence
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SIGGRAPH ’17 Emerging Technologies, July 30 - August 03, 2017, Los Angeles, CA, USA© 2017 Copyright held by the owner/author(s).
ACM ISBN 978-1-4503-5012-9/17/07.
https://doi.org/10.1145/3084822.3084831

Figure 2: TwinCam head
(fixed-azimuth rotation
mechanism).

Figure 3: Schematic of theTwinCam system.

SIGGRAPH ’17 Emerging Technologies, July 30 - August 03, 2017, Los Angeles, CA, USA
while the direction of the lens (i.e., the optical axis) maintains constant orientation. This design1 has two major benefits, namely, lowmotion blur [Agrawal et al. 2009] and latency compensation during
the head rotation. The motion blur is reduced dramatically as compared to a conventional setup of two cameras arranged with parallelaxes because the TwinCam lens position change does not involve
rotation. Although latency exists when the TwinCam head baserotates to capture a correct binocular image following the HMD rotation, the omni-directional images captured in the previous frame
provide very close images to those obtained after the TwinCam
is rotated. The TwinCam system consists of two omni-directional
live cameras (THETA S, Ricoh), HDMI capture cards (Intensity Pro
4K, Blackmagicdesign), an image control PC, a motor controller(Arduino), a motor (RS405CB, Futaba) with rotation mechanisms,and an HMD (Oculus Rift CV1) as shown in Fig. 3.

2

Simulator Sickness. The International Journal of Aviation Psychology 3 (1993),
203–220. https://doi.org/10.1207/s15327108ijap0303_3

EVALUATIONThe captured image of vertical stripes (horizontal cycle length 120mm), at a distance of 1.0 m, during a rotation of the cameras at 4.76
rad/s had far less motion blur when using the TwinCam configuration (Fig. 4) than that when using conventional parallel configuration (Fig. 5), in which the two cameras rotated symmetrically withthe HMD.
A depth adjustment test of manually moving a piece of white
paper 1.0 m away from the camera revealed that the depth perception by the TwinCam system was far more accurate than that in
the monocular condition for a wide range of observation angles asshown in Fig. 6.
The intensity of the VR sickness symptoms was measured immediately after the participant performed 30 head turns in 60 s in caseof both the TwinCam and the conventional parallel configurations.
A 200 ms latency was introduced before the start of the motor
rotation because such latency is often expected in a telepresence
application. The results of the Simulator Sickness Questionnaire(SSQ) [Kennedy et al. 1993] showed that the TwinCam configuration significantly lowered the SSQ score, which suggests that thelatency was compensated by the locally buffered image.

3

Kento Tashiro et. al.

Figure 4: Very small motion blur in TwinCam configuration.

CONCLUSIONThe TwinCam system achieved both a low motion blur and the latency compensation effect during the omni-directional stereoscopic
live viewing involving fast head rotation. The VR sickness symptoms were relieved in case of the TwinCam system as compared tothe conventional parallel camera configuration; the attendees inour booth will have experienced the effectiveness of this system.

Figure 5: Large motion blur in conventional parallel camera
configuration.

ACKNOWLEDGMENTS
This work was supported by MIC SCOPE Project (#141203019) anda Grant-in-Aid for Scientific Research (A) 26240029, MEXT, Japan.

REFERENCES
Amit Agrawal, Yi Xu, and Ramesh Raskar. 2009. Invertible Motion Blur in Video. ACM
Trans. Graph. 28, 3, Article 95 (July 2009), 8 pages. https://doi.org/10.1145/1531326.
1531401
Robert S. Kennedy, Norman E. Lane, Kevin S. Berbaum, and Michael G. Lilienthal.
1993. Simulator Sickness Questionnaire: An Enhanced Method for Quantifying
1 Patent Application No.PCT/JP2017/ 5161

Figure 6: Depth perception error in TwinCam relative to themonocular (ordinary omni-directional live video) setting.